01 lte-eps overview

LTE/EPS OverviewLTE Extended Introduction course

Module Objectives

After completing this module, the participant should be able to:

• Understand the reasons driving to the LTE/EPS project.• List the LTE/EPS main requirements. • Discuss the future of wireless communications.• Compare LTE/EPS capabilities with other mobile technologies.• Review the 3GPP specification work concerning LTE/EPS.• Identify the major steps in the Network Architecture Evolution towards an LTE/EPS network.• Underline the LTE/EPS key features.• Briefly explain the basics of the LTE Air Interface.• Name the Standardisation bodies around LTE/EPS.• Introduce IMT-Advanced and LTE-Advanced

Module Contents

• Why LTE?• LTE main requirements• LTE versus other Mobile technologies• LTE Specification work• Network Architecture Evolution • LTE key features• Basics of the LTE Air Interface• Standardisation around LTE• IMT-Advanced• LTE Summary

A little bit of History

•New technologies developed in the last 15 years in telecommunication brought available transmission rates to a total new level.

•Two systems have affected the life of nearly everyone:

–mobile communication via 2G network like GSM

–Wired & wireless data connectivity (xDSL & WLAN IEEE 802.11/a/b/g standards)

•3G networks the first step towards a convergence between both networks

The way to LTE: 3 main 3G limitations

1.- The maximum bit rates still are factor of 20 and more behind the current state of the art systems like 802.11n and 802.16e/m. Even the support for higher mobility levels is not an excuse for this.

2.- The latency of user plane traffic (UMTS: >30 ms) and of resource assignment procedures (UMTS: >100 ms) is too big to handle traffic with high bit rate variance efficiently.

3.- The terminal complexity for WCDMA or MC-CDMA systems is quite high, making equipment expensive, resulting in poor performing implementations of receivers and inhibiting the implementation of other performance enhancements.

The way to the Long-Term Evolution (LTE): a 3GPP driven initiative

•LTE is 3GPP system for the years 2010 to 2020 and beyond.

•It shall especially compete with WiMAX 802.16e/m

•It must keep the support for high mobility users like in GSM/UMTS networks

•The architectural changes are big when comparing to UMTS

•.

Mobile Evolution and 3GPP Releases

IP/EthernetRAN

Transport TDM

CDMACDMA

Voice, SMS Web Browsing Media Streaming VoIPReal-Time

MultimediaServicesServices

IP is the foundation for new multimedia services and multiservice transport

Higher access bandwidth, new spectrum available

New subscriber apps

Lower cost per Mbit transport

Shift towards All-IP and flat/mesh topologies

Higher access bandwidth, new spectrum available

New subscriber apps

Lower cost per Mbit transport

Shift towards All-IP and flat/mesh topologies

ATM, FR, HDLC

What Does LTE Mean to End Users & Service Providers?

Performance Improvement Impact to End User Impact to Service Provider

INCREASED SPECTRAL

EFFICIENCYUplink: 2.00-2.25x vs. 3GDownlink: 1.25x vs. 3G

Lower costs – flat fee pricing

Can buy the same amount of spectrum and pump more data to users, or less spectrum to maintain the same level of data usage

Reduced cost per bit

FASTER SPEEDSUplink: 2.00-2.25x vs. 3G

Downlink: 3x vs. 3GPeak rate = 100 Mbps

Faster downloads of multi-media

Better experience with blended services

More ways to splice bandwidth: Same # of users with more bandwidth/user or more users with same bandwidth per user

INCREASED VOICE CAPACITY

10 MHz: 2x vs. 3G

Better voice quality Support more voice users

REDUCED LATENCY< 50 ms

Faster reactions when gaming

Better voice, video telephony

Can reuse applications across wireless and wireline

More capacity for VoIP and TCP-based applications

Comparisons based on average aggregate performance

3GPP Requirements For LTE Spectrum efficiency• DL : 3-4 times HSDPA for MIMO(2,2)• UL : 2-3 times E-DCH for MIMO(1,2)

Frequency Spectrum :• Scalable bandwidth : 1.4, 3, 5, 10, 15, 20MHz• To cover all frequencies of IMT-2000: 450 MHz to 2.6 GHz

Peak data rate (scaling linearly with the spectrum allocation) • DL : > 100Mb/s for 20MHz spectrum allocation• UL : > 50Mb/s for 20MHz spectrum allocation

Capacity• 200 users for 5MHz, 400 users in larger spectrum allocations (active

state)

Latency• C-plane : < 100ms to establish U-plane• U-plane : < 10ms from UE to server

Coverage• Performance targets up to 5km, slight degradation up to 30km

Mobility• LTE is optimized for low speeds 0-15km/h but connection maintained for speeds up to 350 or 500km/h• Handover between 3G & 3G LTE

– Real-time < 300ms– Non-real-time < 500ms

10 | Technical Sales Forum | May 2008

LTE Transforms Wireless Access and Core Networks to All-IP

10 |

LTE Drivers

Wireline Evolution: pushes higher data rates

Wireless Data extensively used:

Pushes more capacity

Flat Rate pricing:

pushes cost efficiency

Other Wireless technologies:

Competition pushes new capabilities

Driving to clear LTE Targets

What are the LTE challenges?

• Best price, transparent flat rate

• Full Internet

• Click-bang responsiveness

• reduce cost per bit

• provide high data rate

• provide low latency

The Users’ expectation… ..leads to the operator’s challenges

Price per Mbyte has to be reduced to remain profitable

User experience will have an impact on ARPU

LTE: lower cost per bit and improved end user experience

UMTS HSPA LTE

Cost per MByte

HSPA LTE HSPA LTE

Throughput Latency

Fact

or 1

0

Factor 2-3

Module Contents


LTE Main Requirements

• Peak data rates to exceed 100 Mbps in DL / 50 Mbps in UL

• Low latency 10-20 msEnhanced consumer experience

• Scalable bandwidth: from 1.4MHz up to 20 MHz

Easy to introduce on any frequency band

• OFDM technology• Spectral efficiency increased (2-4

times compared with HSPA Rel6)

• Flat Architecture, optimized PS• IP based interfaces

Decreased cost / GByte

• Next step for GSM/WCDMA/HSPA

A true global roaming technology

NEXT 7 Slides elaborate these points

Schedule for 3GPP releases

year

UMTS Rel 99/4UMTS Rel 99/4 UMTS Rel 5UMTS Rel 5 UMTS Rel 6UMTS Rel 6 UMTS Rel 7UMTS Rel 7

2007200520032000 2008

IMSHSDPA

MBMSWLAN IWHSUPA

IMS EvolutionLTE Studies

3GPP Specification work:

2009

• LTE have been developed by the 3GPP, the same standardization organization responsible fro WCDMA/HSPA. The target has been simple multimode implementation and backwards compatibility.

• HSPA and LTE have in common:

– Sampling rate using the same clocking frequency

– Same kind of Turbo coding

• The harmonization of these parameters is important as sampling and Turbo decoding are typically done on hardware due to high processing requirements.

• .

UMTS Rel 8UMTS Rel 8

LTE & EPC

A true global roaming technology

• Next step for GSM/WCDMA/HSPA Networks, but also for cdma2000 operators

Comparison of Throughput and Latency (1/2)

Enhanced consumer experience:- drives subscriber uptake

- allow for new applications

- provide additional revenue streams

• Peak data rates to exceed 100 Mbps in DL / 50 Mbps in UL

HSPA R6

Max. peak data rate

Mb

ps

Evolved HSPA (REL. 7/8, 2x2 MIMO)

LTE 2x20 MHz (2x2 MIMO)

LTE 2x20 MHz (4x4 MIMO)

Downlink

Uplink

350

300

250

200

150

100

50

0

173 Mbps in DL57 Mbps in UL

Comparison of Throughput and Latency (2/2)

HSPAevo (Rel8)

LTE

* Server near RAN

Latency (Roundtrip delay)*

DSL (~20-50 ms, depending on operator)

0 20 40 60 80 100 120 140 160 180 200

GSM/EDGE

HSPARel6

min

max

ms

Enhanced consumer experience:- drives subscriber uptake

- allow for new applications

- provide additional revenue streams

• Reduce Latency:•User Plane 10-20 ms•Control Plane < 100 ms

IDLE“ECM_Idle”

(no resources)

ACTIVE“ECM_

Connected”(EPS Bearer

allocated)

< 100 ms

USER PLANE Latency: CONTROL PLANE Latency:

Scalable bandwidth

• Scalable bandwidth: from 1.4MHz up to 20 MHz

Easy to introduce on any frequency band: Frequency Refarming(Cost efficient deployment on lower frequency bands supported)

Scalable Bandwidth

Urban

2006 2008 2010 2012 2014 2016 2018 2020

Rural

2006 2008 2010 2012 2014 2016 2018 2020

or

2.6 GHz

2.1 GHz

2.6 GHz

2.1 GHz

LTE

UMTS

UMTS

LTE

900 MHz

900 MHz GSM

or

GSM UMTS

LTE

LTE

LTE

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

HSPA R6 HSPA R6 +UE

equalizer

HSPA R7 WiMAX LTE R8

bp

s/H

z/c

ell

DownlinkUplink

Increased Spectral Efficiency

• All cases assume 2-antenna terminal reception

• HSPA R7, WiMAX and LTE assume 2-antenna BTS transmission (2x2 MIMO)

ITU contribution from WiMAX Forum shows downlink 1.3 and uplink 0.8 bps/Hz/cell

• OFDMA technology increases Spectral efficiency

•LTE target is to increase 2-4 times the HSPA R6 spectral efficiency•HSPA R7 and WiMAX have Similar Spectral Efficiency

Simulations show LTE can provide: >3 times HSPA R6 spectral efficiency in DL >2 times HSPA R6 spectral efficiency in UL

Reduced Network Complexity

• Flat Architecture, Optimized PS Domain

• IP based Interfaces

• Flat Architecture: 2 nodes architecture• IP widely used as the network layer in the protocol stack of all interfaces (both for the control and user plane)

Access Core Control

Evolved Node B Gateway

IMS HLR/HSS

Flat, IP based architecture

Internet

MME

LTE Requirements Summary

1.- Simplify the RAN:- Reduce the number of different types of RAN nodes, and their

complexity.- Minimize the number of RAN interface types.

2.- Increase throughput.3.- Reduce latency (which is a prerequisite for CS replacement).4.- Improve spectrum efficiency.5.- Provide greater flexibility with regard to the frequency bands in which the system may be deployed (Frequency Refarming)6.- Migrate to an optimized PS domain, with no CS domain in the core network.7.- Provide efficient support for a variety of different services. Traditional CS services will be supported via VoIP, etc.8.- Minimise the presence of single points of failure in the network above the evolved Node Bs (eNBs).9.- Support inter-working with existing 3G systems and non-3GPP specified systems in order to support handover to/from these systems. 10.- All-IP transport network.11.- Improve terminal power efficiency.

Module Contents


data rates

< 1 Gbps

mobility

GSM/IS95

AMPS

WCDMA/cdma2000 HSPA LTE

802.11a/b/g802.11a/b/g

< 100 Mbps< 50 Mbps< 10 Mbps< 1 Mbps< 200 kbps

time

2010200520001990

HIGH

LOW

History and Future of Wireless

1G

2G3G 3G Enhacements 3G Evolution

802.11 802.11nWLAN Family

WiMAX Family

802.16eMobile WiMAX

802.16eMobile WiMAX802.16a/d

Fixed WiMAX802.16a/d

Fixed WiMAX

Module Contents


• End 2004 3GPP workshop on UTRAN Long Term Evolution• Beginning 2005 Study item started• December 2005 Multiple Access selected• March 2006 Functionality split between radio and core• September 2006 Study item closed & approval of the work items• December 2007 1st version of all radio specs approved • December 2008 3GPP REL. 8: content Finalized• March 2009 Protocol Freezing (Backwards compatibility starts)

3GPP LTE specification work completed so far

20082004 2005 2006 2007

Multiple Access Decision

RAN/CN functional split

PDCP moved from CN to EUTRAN

FDD/TDD Frame Structure Alignment

2009

LTE Workshop

Start of the Study

Close Study and Start Work Item

1st full set of specifications

Content Finalized

Protocol Freezing¡

Standardization

Technology

3GPP Release 9 and beyond

During 2008 the 3GPP has analyzed topics to be included in the Release 9 .

Examples of those topics are:

•LTE MBMS (Multimedia Broadcast Multicast System): operation of a broadcast carrier.

•A very FEW Self Optimized Networks (SON)

•Network Sharing

•Enhanced VoIP support in LTE

•Requirements for LTE Multi-band and Multi-Radio base stations

Japan

2008 2009 2010 2011 & beyond

Demonstrate LTE Air Interface

Performance

Operator Trials. Friendly-use

networks

LTE Networks Launch:

commercial solution available

Large Scale LTE Networks.

VoIP service optimized.

3GPP R9

Module Contents


NEXT 7 Slides elaborate these points

Network Architecture Evolution (1/4)

Node B RNC SGSN GGSN

Internet

3GPP Rel 6 / HSPA

User plane

Control Plane

• Original 3G architecture.

• 2 nodes in the RAN.

• 2 nodes in the PS Core Network.

• Every Node introduces additional delay.

• Common path for User plane and Control plane data.

• Air interface based on WCDMA.

• RAN interfaces based on ATM.

• Option for Iu-PS interface to be based on IP.


Direct tunnel

3GPP Rel 7 / HSPA

Internet

Node B RNC

SGSNGGSN

User plane

Control Plane

• Separated path for Control Plane and User Plane data in the PS Core Network.

• Direct GTP tunnel from the GGSN to the RNC for User plane data: simplifies the Core Network and reduces Signalling.

• First step towards a flat network Architecture.

• 30% core network OPEX and CAPEX savings with Direct Tunnel.

• The SGSN still controls traffic plane handling, performs session and mobility management, and manages paging.

• Still 2 nodes in the RAN.


Direct tunnel

3GPP Rel 8 / LTE

Internet

Evolved Node B

MME

SAE GW

• LTE takes the same Flat architecture from Internet HSPA.

• Air interface based on OFDMA.

• All-IP network.

• New spectrum allocation (i.e 2600 MHz band)

User plane

Control Plane

Network Architecture Evolution - Summary

Node B RNC SGSN GGSN

Internet

3GPP Rel 6 / HSPA

Direct tunnel

3GPP Rel 7 / HSPA

Internet

Node B RNC

SGSNGGSN

Direct tunnel

3GPP Rel 8 / LTE

Internet

Evolved Node B

MME

SAE GW

Module Contents


LTE/SAE Key Features – EUTRAN 1/2

Evolved NodeB•No RNC is provided anymore•The evolved Node Bs take over all radio management functionality.•This will make radio management faster and hopefully the network architecture simpler

IP transport layer•EUTRAN exclusively uses IP as transport layer

UL/DL resource scheduling•In UMTS physical resources are either shared or dedicated•Evolved Node B handles all physical resource via a scheduler and assigns them dynamically to users and channels•This provides greater flexibility than the older system

LTE/SAE Key Features – EUTRAN 2/2

QoS awareness

•The scheduler must handle and distinguish different quality of service classes

•Otherwise real time services would not be possible via EUTRAN

•The system provides the possibility for differentiated services

Self configuration

•Currently under investigation

•Possibility to let Evolved Node Bs configure themselves

•It will not completely substitute the manual configuration and optimization.

LTE/SAE Key Features – EPC (Evolved Packet Core)

Packet Switched Domain only•No circuit switched domain is provided•If CS applications are required, they must be implemented via IP•Only one mobility management for the UE in LTE.

3GPP (GTP) or IETF (MIPv6) option•The EPC can be based either on 3GPP GTP protocols (similar to PS domain in UMTS/GPRS) or on IETF Mobile IPv6 (MIPv6)

Module Contents


TDMA

f

t

f

• Time Division

FDMA

f

f

t

• Frequency Division

CDMA

f

tcode

s

f

• Code Division

OFDMA

f

f

t

• Frequency Division

• Orthogonal subcarriers

Multiple Access Methods User 1 User 2 User 3 User ..

OFDM is the state-of-the-art and most efficient and robust air interface

LTE/SAE Air Interface 1/3

OFDMA •Downlink multiplexing•OFDMA stands for Orthogonal Frequency Division Multiple Access•Receiver complexity is at a reasonable level •it supports various modulation schemes from BPSK, QPSK, 16QAM to 64 QAM.

SC-FDMA•Uplink multiplexing•SC-FDMA stands for Single Carrier Frequency Division Multiple Access, a variant of OFDMA•The advantage against OFDMA to have a lower PAPR (Peak-to-Average Power Ratio) meaning less power consumption and less expensive RF amplifiers in the terminal.

64QAMModulation


MIMO •Multiple Input Multiple Output •LTE will support MIMO as an option, •It describes the possibility to have multiple transmitter and receiver antennas in a system. •Up to four antennas can be used by a single LTE cell (gain: spatial multiplexing) •MIMO is considered to be the core technology to increase spectral efficiency.

HARQ •Hybrid Automatic Retransmission on reQuest•HARQ has already been used for HSDPA and HSUPA. •HARQ especially increases the performance (delay and throughput) for cell edge users.• HARQ simply implements a retransmission protocol on layer 1/layer 2 that allows to send retransmitted blocks with different coding than the first one.

TX RX

Tx RxMIMO

Channel

HARQ Hybrid Automatic Repeat Request


Scalable bandwidth• LTE air interface allows to drive cells with 1.4 MHz, 3 MHz, 5 MHz, 10MHz, 15MHz & 20 MHz. •This gives the required flexibility for operators to use spectrum allocations not available to a non-scalable wide-band or ultra-wide-band system. DL: OFDMA

UL: SC-FDMA

scalable

Module Contents


Standardisation around LTE

Next Generation Mobile Networks. Is a group of mobile operators, to provide a coherent vision for technology evolution beyond 3G for the competitive delivery of broadband wireless services.More in www.ngmn.org

Collaboration agreement established in December 1998. The collaboration agreement brings together a number of telecommunications standards bodies: ARIB, CWI, ETSI, ATIS, TTA, and TTC.

More in www.3gpp.org

LTE/SAE Trial Initiative. Is was founded in may 2007 by a group of leading telecommunications companies.Its aim is to prove the potential and benefits that the LTE technology can offer. More in http://www.lstiforum.com/

3GPP List of Specification Series

36 Series contains most part of LTE related

specifications for Radio

NGMN Alliance

LTE /SAE approved by the NGMN as first technology which broadly meets NGMN requirements

LSTI (LTE-SAE Trial Initiative)- joint test bed for LTE worldwide

…….. active parties within LSTI

LSTI initiatives goals/objectives

• demonstrate feasibility and capabilities of 3GPP LTE-SAE technology under real world conditions. Indoor & outdoor tests

• accelerate development of 3GPP specification by identifying shortcomings out of test phases

• reduce risk of market introduction of new LTE-SAE technology

Friendly customer trials

PR

2007 2008 2009 2010

Public Relation work

InteroperabilityIODT

IOT

Trials

Test of basic functions

Proof of Concept

Schedule & Program Office:

Test of OFDM Air Interface

Module Contents

• Why LTE?• LTE main requirements• LTE versus other Mobile technologies• LTE Specification work• Network Architecture Evolution • LTE key features• Basics of the LTE Air Interface• Standardisation around LTE• IMT-Advanced

LTE Advanced

data rates 1 Gbps

Mobility

100 Mbps10 Mbps1 Mbps

LOW

HIGH

IMT-2000 IMT-2000 Evolution IMT- Advanced

WCDMA HSPA LTE LTE-Advanced

•IMT-Advanced is a concept for mobile systems beyond IMT-2000

•During 2009, ITU will submit a request for IMT-Advanced candidates. Radio interface submission deadline is expected October 2009.

•IMT Target bit rates:

– 100Mbps for high mobility users

– 1Gbps for low mobility users

•3GPP has already started to work on the IMT-Advanced targets under the name: LTE-Advanced. To be part of 3GPP REL 10.

01 lte-eps overview

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